The Additional Solar IR Break Beam Alert Transmitter from Dakota Alert includes 2 point to point IR beam transmitters that can be mounted up to 300ft apart from each other. These transmitters are accessories to the Solar IR Break Beam Alert System and require the receiver that comes with this system in order to work. The IR beam transmitters are wireless and each has a solar charger located at the top of the device to power its rechargeable lithium ion batteries. Because there are no wires to run in order to power the transmitters it provides more flexibility in where the user can set the system up and takes the hassle out of burying or covering wires. The point to point sensors infrared beam is not visible to the naked eye and as a result, approaching guests or intruders will not be aware that they have made their presence known. The sensors will not be set off by motion outside of its beam such as birds or even falling leaves. Another benefit to the wireless design is that it is easier to mount each transmitter high enough so that the IR beam will not be set off by animals such as a wandering dog.